The present disclosure relates to a multilayer ceramic electronic part capable of having improved reliability by improving corner coverage performance of an external electrode, and a board having the same mounted thereon.
In accordance with the recent trend toward miniaturization of electronic products, the demand for multilayer ceramic electronic parts having a small size and high capacitance has increased.
In accordance with the demand for multilayer ceramic electronic parts having a small size and large capacitance, external electrodes of multilayer ceramic electronic parts have also been thinned.
According to the related art, generally copper is used as a conductive metal in order to form external electrodes, an external electrode paste is prepared by mixing glass, a base resin, an organic solvent, and the like, with this metal, the external electrode paste is applied to both end surfaces of ceramic bodies. Then, the metal in the external electrodes is sintered by sintering the ceramic bodies.
The external electrode paste contains a conductive metal such as copper (Cu) as a main material to thereby ensure a chip sealing property and electrical conductivity between the external electrodes and chips, and contains glass as an auxiliary material to thereby serve to provide adhesion between external electrodes and chips simultaneously with filling an empty space at the time of sintering shrinkage of the metal.
However, as the multilayer ceramic electronic parts are miniaturized and have large capacitance, in order to secure the capacitance, a design for increasing the number of stacked internal electrodes and decreasing thicknesses of upper and lower cover layers has been generally applied.
Therefore, internal electrodes are formed to the vicinity of corner portions of the ceramic bodies at which a thickness is decreased at the time of forming external electrodes, such that the multilayer ceramic electronic parts may be easily exposed to physical or chemical impacts.
For example, as external electrodes of multilayer ceramic electronic parts have been thinned, thicknesses of the external electrodes in the vicinity of the corner portions of the ceramic bodies have been further decreased to reduce corner coverage performance. Therefore, a problem such as infiltration of a plating solution may occur.
Further, in the case of external electrodes used in high capacitance electronic parts, at the time of sintering the external electrodes, in order to decrease thermal impacts, a material capable of being sintered at a relatively low temperature may be used. For example, in the case of glass softened at a relatively low temperature, the external electrodes have relatively weak acid resistance at the time of plating. Due to these features, in the case in which plating layers are formed on outer portions of external electrodes, the plating solution may easily infiltrate, which becomes a main cause of deteriorating product quality due to deterioration of moisture resistance reliability.